The present invention relates to an image processing system, a projector, a program, an information storage medium, and an image processing method capable of correcting image distortion.
There may be a case where image distortion occurs depending on the relative angle formed by the optical axis of projection light from an image projection device, such as a projector, and a projection target such as a screen, whereby keystone distortion occurs in the vertical direction or horizontal direction.
Therefore, an image projection device must project an image while eliminating image distortion.
A conventional image projection device with an image distortion correction function includes an angle sensor, and corrects image distortion in the vertical direction using the angle sensor, but cannot correct image distortion in the horizontal direction.
In the case of correcting image distortion in the horizontal direction, a user points at the four corners of the screen using a mouse or the like, and the image projection device semi-automatically corrects the image distortion based on the point information. However, it is troublesome for the user to point at the four corners of the screen using a mouse or the like.
In order to solve such a problem, Japanese Patent Application Laid-open No. 2000-241874 employs a method in which a screen and an all-white image on the screen are sensed by using a monitor camera, and keystone distortion is adjusted based on the edge points of the screen and the edge points of the all-white image, for example.
However, in the method of adjusting keystone distortion using the information on the shape of the screen as in Japanese Patent Application Laid-open No. 2000-241874, the user necessarily uses the screen. Therefore, in the case where the projector projects an image onto a frameless projection target such as a wall, keystone distortion cannot be corrected by using the method disclosed in Japanese Patent Application Laid-open No. 2000-241874. Moreover, since the method disclosed in Japanese Patent Application Laid-open No. 2000-241874 assumes that the screen is rectangular, this method is lacking in universality.